IMHO, attempts to show literate programming on screen are doomed to meet with mediocre success. DEK invented literate programming with printed books in mind. I dare say that the only successful literate programs are books printed on paper.

First, in a printed book, it is easier to find a previous page and compare a fragment on it with the current fragment. Second, a printed book has no links tempting you with the words "CLICK ME" to disrupt the flow so you can read it from cover to cover with fewer distractions. Third, anecdotally, I can see flaws much easier on a printout than on screen, both in programs and in texts.